Means for mounting objects in electron microscopes



K. KR'AUsE 2,264,210 MEANS FOR MOUNTING OBJECTS IN ELECTRON MICROSCOPES Nov. 25, 1941.

Filed Aug. 18, 1939 W n e Ov w W. r a l n V Q? Q wf f r; N7 L ,nu l l Q x Q m Q M &\^/ z L Patented Nov. 25, 1941 MEAN S FOR MOUNTING OBJECTS IN ELEC- TRON IMICROSCOPES Karl Krause, Berlin, Germany Application August 18, 1939, Serial No. 290,916

` In Germany November 19, 1937 (Cl. Z50-49.5)

6 Claims.

This invention relates to means for. mounting objects in an electron-microscope.

Electron-microscopes provided with means for mounting objects are known in which a conical metal body is arranged in a conical guide. It is, however, known that conical guides require grease for satisfactory operation.

In contradistinction thereto, the means according to the invention consist of an optically ground bar provided with a number of openings at right-angles to its axis for receiving objects. The bar is guided in a sleeve and the sleeve and bar are additionally sealed outside the electronmicroscope by a packing.

By means of the optically ground bar according to the invention the use of grease as a sealing agent is unnecessary and at the same time a number of objects can be inserted in the object carrier which may be brought successively into the path of the rays for examination. In the known air lock arrangements only a single object is provided or two plates or films inside a cone.

In the arrangement illustrated in the accompanying drawing as a constructional example, ve chambers are provided, the number of which could be further increased if necessary.

A further advantage is seen in the exchanging of the objects. This is effected, according to the invention, for example by simply rotating the bar with an object holder so that the object can drop out and it is not necessary to push the object out by means of a more or less long rod.

The invention also makes it possible to provide for cooling or heating by the arrangement of passages which may be of great importance in examining delicate organic preparations if these, for example, are liable to be frozen by extensive cooling.

The arrangement according to the invention is illustrated diagrammatically and by way of example in the accompanying drawing. The gure is a cross section of one constructional example.

Referring to Figure l, a tube c passes through the vacuum space a of an electron-microscope b. In the cylinder c an optically ground rod d is arranged having a number of openings ce1-e5. The objects are inserted in the openings, for example by means of the object holders f, as seen in the opening es which is shown broken away. The object rod d and the sleeve c are further sealed outside the electron-microscope b by a packing g.

In order that the temperature of the object may be controlled without affecting the vacuum, a passage h parallel to the axis of the rod d may be provided in addition to the object chambers for the passage of cooling liquid or of electrical conductors.

In order, when exchanging objects, to pump out the openings in the rod and to intercept any air, the invention further provides, between the tube c and the rod d, an annular hollow space i which is connected to a vacuum pipe.

During these operations the vacuum in the interior, apart from small quantities of air which enter, is completely maintained, so that rapid operation is ensured (for example in a series of examinations). It is possible to introduce a number of objects into the high vacuum space at one time. By the use of an optically ground bar which bears against the inner surface of the tube c with a suction eiect and, on account of the provision of the packing, it is not necessary to use grease. The invention can, therefore, also be employed when cooling with liquid is used.

While the invention has been described with reference to specic structural details it will be appreciated that changes may be made therein. Such modications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

l. In an electron microscope, an electric discharge tube, a cylinder extending through the discharge tube and sealed with respect thereto, said cylinder having an aperture therein for the passage of electrons therethrough, a rod slidable in said cylinder for supporting an object to be analyzed adjacent said aperture, and the periphery of said rod tting the inner surface of said cylinder in a vacuum-tight manner whereby the object carried by said rod may be longitudinally moved with respect to said aperture without altering the pressure within said discharge tube.

2. In a vacuum electric discharge tube, a cylinder extending through the tube and sealed with respect thereto, said cylinder having an aperture therein for the passage of electrons therethrough, a rod slidable in said cylinder and having transverse openings therein for receiving objects to be subjected to the electrons adjacent said aperture, and the. peripheral surface of said rod engaging the inner surface of said cylinder in a vacuum-tight manner whereby the objects arranged in the openings of said rod may each be positioned adjacent said aperture without disturbing the vacuum within said discharge tube.

3. In an electron microscope, a vacuum electron tube, a cylinder extending transversely through the electron tube and sealed with respect thereto, said cylinder having an aperture therein extending transversely therethrough for the passage of electron rays through the aperture, a rod slidable in said cylinder and having openings spaced therealong each extending transversely through the rod for receiving objects to be subjected to the electron rays passing through said aperture, and the peripheral surface of said rod fitting the inner surface of said cylinder in a vacuum-tight manner whereby the rod may be rotated and longitudinally moved in the cylinder without disturbing the vacuum Within said electron tube.

4. In an electron microscope, a vacuum electron tube, a cylinder extending transversely through the electron tube and sealed with respect thereto, said cylinder having an aperture therein extending transversely therethrough for the passage of electron rays through the aperture, a rod slidable in said cylinder and having openings spaced therealong each extending transversely through the rod for receiving objects to be subjected to the electron rays passing through said aperture, the peripheral surface of said rod fitting the inner surface of said cylinder in a vacuum-tight manner whereby the rod may be rotated and longitudinally moved in the cylinder without disturbing the vacuum within said electron tube, and said cylinder having an annular space outside said electron tube for removing air trapped within said openings.

5. In an electron microscope, a vacuum electron tube, a cylinder extending transversely through the electron tube and sealed with respect thereto, said cylinder having an aperture therein extending transversely therethrough for the passage of electron rays through the aperture, a rod slidable in said cylinder and having openings spaced therealong each extending transversely through the rod for receiving objects to be subjected to the electron rays passing through said aperture, the peripheral surface of said rod fitting the inner surface of said cylinder in a vacuum-tight manner whereby the rod may be rotated and longitudinally moved in the cylinder without disturbing the vacuum without said electron tube, and packing means for further sealing the periphery of the rod with respect to said cylinder.

6. In an electron microscope, an electric discharge tube, a cylinder extending through said tube and sealed with respect thereto, said cylinder having a transverse aperture therethrough for the passage of electrons, a rod slidable and rotatable in said cylinder and having transverse openings therethrough for receiving objects to be subjected to the electrons passing through said aperture, the peripheral surface of said rod engaging the inner surface of said cylinder in a vacuum-tight manner whereby the objects arranged in the openings of said rod may each be positioned adjacent said aperture Without disturbing the vacuum within the discharge tube, and said rod having an axially extending passage therein.

KARL KRAUSE. 

